Wireless G speeds decreased after upgrade?

[Nicholas Hughes]

Hello everyone,

I'm having a hard time figuring out why we lost half of our wireless speed over g radios after we went lightweight.

We just upgraded from autonomous to lightweight with a 5508 controller on software version 7.0.116.0. 

At our venue, before an event we do speed tests at commonly used wireless areas and would get 15Mbs - 20 Mbs to speakeasy.  After the upgrade, speeds are cut in half for the g radios (usually it's 7-10Mbs). 

The only clients that can get this speed are the clients that are capable of using the A radio.  Also, if we connect to a linksys AP (it's a temporary band-aid for a dead AP) we get the 15-20 speeds. 

These are all 1131ag AP's.    The controller has the default config on the b/g/n radios, the client shows it's connected at 54Mbs.  QoS is also default.  All SSID's are WPA2-PSK with default everything else.

I've tested the speeds on an AP with 8 users on it, and on an AP where I am the only one on the AP.  The network usually only has 12 active associations at a time during the day over our 8 AP's.  The most I've ever seen on 1 AP during the day is 10 users.

Anyone have an idea why we lost this speed using the same AP's but we can get the correct speed via the A-radio or another autonomous AP?

Thank you,

Nick

[Salil Prabhu · Accepted solution]

Hi Nick,

Can your check the AP power levels { Wireless ---> Access point --> 802.11b/g } and Channel Utilization { Monitor --.>Accesspoints --> 802.11b/g }  ..

If channel utilization is high, you may see slugishness on wireless network.

To reduce channel utilization :

1) Disable 1,2 mbps rate { wireless --> 802.11b/g --> network } . Legacy clients like B only clients may be affected with this change..

2) Proper AP placement and AP power levels.

3) Lesser the SSIDs the better it is..

Thanks..Salil

[Nicholas Hughes]

Power and channels are controlled by the controller.  The power varies from 1 to 2.  The A radios are usually always 1 and those are working fine.  The placement of the AP's shouldn't matter since it's not setup for full coverage of the arena, right now we have only 8 AP's in this arena.  Those 8 are only placed in specific areas.  I'm sitting 10 feet from the AP i'm connecting to.  If I turn that off, I might be able to connect to the next closest but barely be able to pass traffic.

I will try the disabling the 1, 2 mbps rate and reply with the results.

We only have 4 SSID's.

[Nicholas Hughes]

Looks like the auto selecting of the channels wasn't all that smart.  Just a shot in the dark, I manually set the channel to the AP to 11 and speeds increased.  There must be something in this building causing interference with channel 1.  I tried turning off all AP's except this 1 and it was still on channel 1 and the speeds were slow.  I changed it to 11 and it's back to normal.  Since the AP's are so far apart, they just stayed with channel 1 since they didnt't have any neighbors.  Hence the same problem in different locations.  Thanks for all the help guys.

[Leo Laohoo]

Is "G" enabled?

[Nicholas Hughes]

It is enabled, and it shows on my client that it has connected to G at 54Mbs

[Samuel Seo]

I have also faced simialar issue. However, I am still not able to resolve this problem.

[abukuru95]

Hi Guys, I would suggest you go to Wireless -> 802.11b/g/n -> Network and make sure that the higher speed are also supported.

do not forget to rate if this helps.

regards

[Nicholas Hughes]

They are supported and my client says I connect at 54 Mbps

[abukuru95]

try configuring a separate SSID for only G clients and then test the speeds on this.

on the wireless LAN configuration page, Radio policy, choose G only and test.

this may work !!

[Nicholas Hughes]

Nope, same results.  This is one of the stranger issues I've seen.

[abukuru95]

it may take time before you see it and you need to reassociate your clients

[abukuru95]

try testing with security disabled

[Nicholas Hughes]

SSID with no security for only G radios is still half the speed of the A radios.  Cisco came out with a new software version yesterday.  I may try that but I have to wait until after hours.

[abukuru95]

Nicholas, you may also have to see that there's no Qos restriction for traffic on whatever subnet concerning these G clients.can you place a wired client on the same vlan as one of your G clients and see if you have a required speed? you may configure a switch port on the network and connect a Pc. otherwise reset the WLC to factory defaults as last option.

rate if this helps.